Error creating a screenshot in the winapi service - winapi

Question

I have a client application written in C++, and a server written in Python. This application has several functions, including getting a screenshot of the client's desktop and getting this file on the server.
When I run these programs without any add-ons, everything works. I need to upload my client to the service, and I do it through CreateProcess[client file] inside of my service. All other functions besides the screenshot work with this approach.
Server code, getting a screenshot:
if (cState == State.GETTING_SCREENSHOT):
message = "SCREENSHOT".encode('utf-8')
MySend(client_sock , message)
curr_number = 0
with open("settings.txt" , 'r') as settings:
curr_number_str = settings.readline()
curr_number = int(curr_number_str)
with open("settings.txt" , 'w') as settings:
settings.write(str(curr_number + 1))
screenshot_file = str(curr_number) + ".png"
with open(screenshot_file , 'wb') as file:
while True:
data = MyRecv(client_sock , 40000)
data_arr = bytearray(data)
if (data_arr[:10] == b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'):
continue
if (b'ENDOFF' in data):
break
file.write(data)
cState = State.INPUT_COMMAND
Client code:
case SENDING_SCREENSHOT_IN_PROGRESS:
{
wchar_t PathToLocalAppDataFolder[MAX_PATH];
if (FAILED(SHGetFolderPathW(NULL, CSIDL_LOCAL_APPDATA, NULL, 0, PathToLocalAppDataFolder))) {
LoadMessage("Error in ShGetFolderPathW");
break;
}
std::wstring PathToScreenshot = std::wstring(PathToLocalAppDataFolder) + L"\\1.png";
if (!SaveScreen(PathToScreenshot.c_str())) {
LoadMessage("SaveScreen api-func failed");
break;
}
HANDLE hFile = CreateFile(PathToScreenshot.c_str(), GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
if (hFile == INVALID_HANDLE_VALUE) {
LoadMessage("Can not open screenshot file");
break;
}
DWORD dwRead = 1;
BYTE buffSend[BIG_BUFFLEN];
while (dwRead) {
ZeroMemory(buffSend, BIG_BUFFLEN);
dwRead = 0;
ReadFile(hFile, buffSend, BIG_BUFFLEN, &dwRead, NULL);
MySend(ClientSoc, (char*)buffSend, dwRead, 0);
}
CloseHandle(hFile);
char message[SMALL_BUFFLEN] = "ENDOFFILE";
MySend(ClientSoc, message, BIG_BUFFLEN, 0);
DeleteFile(PathToScreenshot.c_str());
cState = WAITING_FOR_INCOMING_COMMAND;
break;
}
Service code:
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <iostream>
#include <shlobj_core.h>
#include <string>
#include "api.h"
#include <fstream>
#pragma comment(lib , "API.lib")
#pragma warning(disable:4996)
wchar_t SERVICE_NAME[] = L"RemoteController";
bool isCreate = FALSE;
SERVICE_STATUS ServiceStatus = { 0 };
SERVICE_STATUS_HANDLE hServiceStatus; //StatusHandle
HANDLE ServiceStopEvent = INVALID_HANDLE_VALUE;
VOID WINAPI ServiceMain(DWORD argc, LPTSTR* argv);
VOID WINAPI ServiceCtrlHandler(DWORD CtrlCode);
DWORD WINAPI ServiceWorkerThreadEntry(LPVOID lpParam);
VOID Install(VOID);
BOOL dirExists(const wchar_t* dir_path);
int main(int argc, char* argv[]) {
FreeConsole();
Install();
SERVICE_TABLE_ENTRY ServiceTable[] = {
{SERVICE_NAME , (LPSERVICE_MAIN_FUNCTION)ServiceMain} ,
{NULL , NULL}
};
if (StartServiceCtrlDispatcher(ServiceTable) == FALSE) {
LoadMessage("Service.exe : StartServiceCtrlDIspathcer error");
return GetLastError();
}
return 0;
}
VOID WINAPI ServiceMain(DWORD argc, LPTSTR* argv) {
DWORD Status = E_FAIL;
hServiceStatus = RegisterServiceCtrlHandler(
SERVICE_NAME,
ServiceCtrlHandler
);
if (hServiceStatus == NULL) {
LoadMessage("Service.exe : RegisterServiceCtrlHandler failed");
return;
}
ZeroMemory(&ServiceStatus, sizeof(ServiceStatus));
ServiceStatus.dwServiceType = SERVICE_WIN32_OWN_PROCESS | SERVICE_INTERACTIVE_PROCESS;
ServiceStatus.dwControlsAccepted = 0;
ServiceStatus.dwCurrentState = SERVICE_START_PENDING;
ServiceStatus.dwWin32ExitCode = 0;
ServiceStatus.dwServiceSpecificExitCode = 0;
ServiceStatus.dwCheckPoint = 0;
if (SetServiceStatus(hServiceStatus, &ServiceStatus) == FALSE) {
LoadMessage("Service.exe : SetServiceStatus failed");
}
ServiceStopEvent = CreateEventW(NULL, TRUE, FALSE, L"RemoteControllerEvent");
if (ServiceStopEvent == NULL) {
ServiceStatus.dwControlsAccepted = 0;
ServiceStatus.dwCurrentState = SERVICE_STOPPED;
ServiceStatus.dwWin32ExitCode = GetLastError();
ServiceStatus.dwCheckPoint = 1;
if (SetServiceStatus(hServiceStatus, &ServiceStatus) == FALSE) {
LoadMessage("Service.exe : SetServiceStatus failed");
return;
}
}
//start
ServiceStatus.dwControlsAccepted = SERVICE_ACCEPT_STOP;
ServiceStatus.dwCurrentState = SERVICE_RUNNING;
ServiceStatus.dwWin32ExitCode = 0;
ServiceStatus.dwCheckPoint = 0;
if (SetServiceStatus(hServiceStatus, &ServiceStatus) == FALSE) {
LoadMessage("Service.exe : SetServiceStatus failed");
}
HANDLE hThread = CreateThread(NULL, 0, ServiceWorkerThreadEntry, NULL, 0, NULL);
WaitForSingleObject(hThread, INFINITE);
CloseHandle(ServiceStopEvent);
ServiceStatus.dwControlsAccepted = 0;
ServiceStatus.dwCurrentState = SERVICE_STOPPED;
ServiceStatus.dwWin32ExitCode = 0;
ServiceStatus.dwCheckPoint = 3;
if (!SetServiceStatus(hServiceStatus, &ServiceStatus) == FALSE) {
LoadMessage("Service.exe : SetServiceStatus failed");
}
return;
}
VOID WINAPI ServiceCtrlHandler(DWORD CtrlCode) {
switch (CtrlCode) {
case SERVICE_CONTROL_STOP:
if (ServiceStatus.dwCurrentState != SERVICE_RUNNING) break;
ServiceStatus.dwControlsAccepted = 0;
ServiceStatus.dwCurrentState = SERVICE_STOP_PENDING;
ServiceStatus.dwWin32ExitCode = 0;
ServiceStatus.dwCheckPoint = 4;
if (SetServiceStatus(hServiceStatus, &ServiceStatus) == FALSE) {
LoadMessage("Service.exe : SetServiceStatus failed");
return;
}
SetEvent(ServiceStopEvent);
default:
break;
}
}
BOOL dirExists(const wchar_t* dir_path) {
DWORD dwAttributes = GetFileAttributes(dir_path);
if (dwAttributes == INVALID_FILE_ATTRIBUTES) return FALSE;
if (dwAttributes & FILE_ATTRIBUTE_DIRECTORY) return TRUE;
return FALSE;
}
VOID Install(VOID) {
SC_HANDLE schSCManager;
SC_HANDLE schService;
wchar_t curr_path[MAX_PATH];
if (!GetModuleFileName(NULL, curr_path, MAX_PATH)) {
LoadMessage("Service.exe : GetModuleFilename failed");
return;
}
schSCManager = OpenSCManager(
NULL, NULL, SC_MANAGER_ALL_ACCESS
);
if (schSCManager == NULL) {
LoadMessage("Service.exe : OpenSCManager failed[with SC_MANAGER_ALL_ACCESS]");
return;
}
schService = CreateService(
schSCManager, SERVICE_NAME, SERVICE_NAME, SERVICE_ALL_ACCESS,
SERVICE_WIN32_OWN_PROCESS | SERVICE_INTERACTIVE_PROCESS, SERVICE_AUTO_START, SERVICE_ERROR_NORMAL,
curr_path, NULL, NULL, NULL, NULL, NULL);
if (schService == NULL) {
LoadMessage("Service.exe : CreateService failed");
CloseServiceHandle(schSCManager);
return;
}
if (StartService(schService , 0 , NULL) == 0){
LoadMessage("Service.exe : Start service failed");
CloseServiceHandle(schSCManager);
CloseServiceHandle(schService);
return;
}
LoadMessage("\tService instaled");
CloseServiceHandle(schSCManager);
CloseServiceHandle(schService);
}
DWORD WINAPI ServiceWorkerThreadEntry(LPVOID lpParam) {
if (isCreate) {
return ERROR_SUCCESS;
}
isCreate = TRUE;
wchar_t ProgramToRun[MAX_PATH];
ZeroMemory(ProgramToRun , sizeof(ProgramToRun));
SHGetFolderPath(NULL, CSIDL_PROGRAM_FILES, NULL, 0, ProgramToRun);
std::wstring tmp = std::wstring(ProgramToRun) + L"\\RemoteController\\MainClient.exe";
STARTUPINFO si;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
PROCESS_INFORMATION pi;
CreateProcess(tmp.c_str(), NULL, NULL, NULL, FALSE, CREATE_NEW_CONSOLE, NULL, NULL, &si, &pi);
return ERROR_SUCCESS;
}